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United States Department of Agriculture

Agricultural Research Service

Research Project: POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT
2010 Annual Report


1a.Objectives (from AD-416)
To develop and protect export markets for tropical fruit, vegetable, nut, and ornamental crops, with emphasis on expanding and diversifying agriculture and agricultural exports in Hawaii by providing environmentally sound, economically viable systems, treatments, or processes that control quarantine pests, ensure product quality and food safety, and increase product value. The three broad objectives to be addressed include (1)Develop new or improved postharvest treatments, including alternatives to methyl bromide fumigation, for fruit, vegetable, and ornamental crop imports and exports to ensure security against quarantine pests; (2) Develop new or improved postharvest treatments for fruit, vegetable, nut, and ornamental crops to improve product quality and shelf life, reduce or eliminate postharvest disorders or decay, and enhance product value; and (3) Identify, develop or improve preharvest methods for fruit, vegetable, nut, and ornamental crops that enhance postharvest quality and reduce the incidence of quarantine pests that limit exports.


1b.Approach (from AD-416)
Develop target quarantine pest and host commodity control efficacy and product quality data, respectively, using irradiation, controlled-atmosphere temperature treatment, limonene and oils, ozone fumigation, or radio frequency treatment with commodity quality, microbial, biochemical, physical property, or vitamin analyses to meet Objectives 1 and 2; and measure target pest feeding activity to forecast damage, determine insecticide resistance levels, or develop caffeine-based toxicants to meet Objective 3. Foremrly 5320-43000-009-00D (4/05).


3.Progress Report
This is the final report for project 5320-43000-014-00D terminated in April 2010. A Bridge project 5320-43000-015-00D is in place.

Substantial outcomes were realized over 5 years in developing new preharvest and postharvest technologies to ensure security against quarantine pests, and to improve commodity quality, shelf life and value. Quarantine treatment research was conducted on non-fruit fly pests of tropical fruits and vegetables, resulting in treatments for 13 insect pests on ten exported crops. Irradiation research led to approved quarantine treatments for sweetpotato pests, banana moth, white peach scale, and coconut scale, and contributed significantly to the landmark approval by APHIS of generic irradiation treatments for quarantine insects. Also, to facilitate rapid adoption of irradiation as a commercial treatment, the radiotolerance limits for high-value specialty fruits were established. Banana quality, composition, and ripening behavior were not compromised by doses up to 600 Gy, and dragon fruit tolerated doses up to 800 Gy. A number of different heat treatments were developed to control fruit flies in passion fruit, guava, and longan by raising the core temperature to 46°C or 47°C during 2 hours, and holding the temperature for 30-45 minutes. The treatments had minimal effects on fruit quality. The potential of radio frequency energy for use as a heat treatment also was examined for Mediterranean, Malaysian, oriental, and melon fruit fly eggs and larvae. Mediterranean fruit fly was the most thermotolerant among fruit fly species. Statistically valid tests and confidence levels were proposed to confirm non-host status for commodities to fruit flies, and this approach was included in a NAPPO Regional Standard on determining host status determination. In other quarantine research, ozone fumigation (as a replacement for methyl bromide) was shown to be effective in controlling coffee berry borer and coffee leaf rust on green coffee beans imported into Hawaii, without affecting brewed coffee quality. To improve export quality of ornamental plants, novel formulations of limonene and essential oils were developed for control of scales, mealybugs and other waxy insects, and a patent application was filed. Research on a bud-drop problem on Dendrobium orchids led to the discovery that damage was caused by the re-emergence of a particular thrips species (Thrips palmi). Laboratory bioassays showed that this species was resistant to a wide variety of contact insecticides. Field research was conducted that led to the registration of an effective contact insecticide, and growers were able to stop the bud-drop problem. Postharvest research on value-added papaya products was completed. Cultivars with resistance to Enterobacter cloacae, the bacterium that causes internal yellowing (IY) in papaya fruit, were identified, and quality, nutritional, and microbial analyses were completed for fresh-cut and frozen papaya cubes prepared from varieties with varying resistance to IY. Also, Enterobacter sakazakii was identified as a new bacterial pathogen on papaya that causes IY. For macadamia nuts, research was completed to enhance product quality.


4.Accomplishments
1. Guidelines for Exporting ‘Sharwil’ Avocados. Avocados cannot be exported from Hawaii to the continental U.S. without a quarantine treatment to prevent the spread of fruit flies. ARS scientists in Hilo, HI, conducted research on the maturity and infestation potential of ‘Sharwil’ avocados to assist in development of a multi-component systems approach for quarantine security based on poor host status, limited distribution, low prevalence, and postharvest safe-guards. The poor host status of hard, mature green fruit was confirmed, and a maturity index was proposed for ‘Sharwil’ avocados based on 29% dry matter content at harvest. The systems approach for Sharwil will allow Hawaii avocado growers to export fruit to the U.S. continent.

2. Effective Postharvest Dips for Control of Asian Citrus Psyllid. Exports of curry and lime leaves from Hawaii and California were interrupted because the efficacy of various postharvest dip procedures used to remove insects from these commodities had not been verified. ARS scientists at Hilo, HI tested various insecticides and fruit wash products and incorporated these in procedures that provided effective control of the Asian Citrus Psyllid. The information is being used by USDA-APHIS for implementation of procedures which will facilitate the export of these commodities.

3. Evaluating Papaya for Resistance to Internal Yellowing Disease. Bacterial contamination by naturally-occurring Enterobacter cloacae poses a food safety risk and presents an obstacle to the marketing of fresh-cut or frozen papaya products. ARS scientists at Hilo, HI developed an objective method for evaluating papaya germplasm for resistance to E. cloacae, the causal agent of internal yellowing disease. An optimal inoculum concentration differentiated resistant and susceptible papaya germplasm, and a colorimeter distinguished infected from non-infected tissue in yellow- or red-fleshed fruit. The screening method can be used for breeding new resistant papaya cultivars, thus reducing the risk of bacterial contamination and ensuring compliance with food safety standards. Also, the colorimeter technology could be applied commercially to identify and discard processed papaya products infected with E. cloacae.


5.Significant Activities that Support Special Target Populations
Scientists have participated in activities targeting small farmers and minority stakeholders including.
1)testing a modified atmosphere packaging approach for exported papayas;.
2)evaluating local avocado cultivars for small farm production and potential import replacement of Hass avocados;.
3)mentoring native Hawaiian summer interns;.
4)surveying small farms (< 1 acre) for thrips control practices in orchids,.
5)evaluating blueberry cultivars for susceptibility to fruit flies, and.
6)developing irradiation and other quarantine treatments for new invasive pests that limit exports.


Review Publications
Wall, M.M., K.A. Nishijima, M.M. Fitch, and W.T. Nishijima. 2010. Physicochemical, nutritional and microbial quality of fresh-cut and frozen papaya prepared from cultivars with varying resistance to internal yellowing disease. Journal Food Quality. 33: 131-149.

Chen, N.J., Wall, M.M., Roboert, P.E., Follett, P.A. 2009. Variation in Sharwil avocado maturity during the harvest season and resistance to fruit fly infestation. HortScience. 44(6):1655-1661.

Follett, P.A., Armstrong, J.W., Zee, F.T. 2009. Host Status of Blueberry to Invasive Tephritid Fruit Flies in Hawaii. Journal of Economic Entomology. 102(5):1859-1863.

Wall, M.M. 2010. Functional lipid characteristics, oxidative stability, and antioxidant activity of macadamia nut (Macadamia integrifolia) cultivars. Food Chemistry. 121:1103-1108.

Green, S.R., Picchioni, G.A., Murray, L.W., Wall, M.M. 2010. Yield and quality of field-grown Celosia and Gomphrena everlasting cut flowers at four planting densities. HortTechnology. 20(3): 612-619.

Hollingsworth, R.G. 2009. METHODS FOR EXCLUDING SLUGS AND SNAILS ON EXPORTED HORTICULTURAL COMMODITIES. Postharvest Technologies for Horticultural Crops. Vol. 2: 93-119.

Last Modified: 11/22/2014
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